1. Field of the Invention
This invention relates generally to the field of oil wells and other drilling operations. More particularly, the invention relates to the field of abrasive jet perforating in oil and gas wells.
2. Description of the Related Art
Abrasive jet perforating uses slurry pumped under high pressure to perforate tubular goods around a wellbore, where the tubular goods include tubing, casing, and cement. When sand is in the slurry, this technique may be known as sand jet perforating. Abrasive jet perforating has been used to extend a cavity into a surrounding reservoir to stimulate fluid production. Abrasive jet perforating has also been used to cut, such as to completely sever, the tubular goods into two pieces.
Perforating or cutting tubular goods, such as casing, drill pipe, and casing liners, is used within, for example, the oil and gas industry. Most engineering processes focused on the tools' ability to perform certain tasks, such as cutting slots. Conventionally, these tools are tubing conveyed, such as when attached to a production tubing string, which may be a string tripped out a producing well to attach to the tool. Jet perforating tools use a constant, pressurized fluid stream from the surface and receive fluid through a tubing string on which they are lowered.
Lowering the tool on a tubing string has several limitations. For example, the lowering of the string attached to the perforating tool is labor-intensive and can take several hours. In addition, before the perforating string can be lowered, the existing tools and production string already in the well must be removed before the perforating string may be lowered. Likewise, the perforating string must then be removed from the well and the tubing string then reinserted along with the production tools.
As an example, performing perforating or cutting jobs in a producing well with a production tubing string and pump tools such as pump rods and a pump in place in the well would typically comprise the following process: (1) run the pump rods and pump out of the well; (2) run the production tubing string out of the well; (3) run a jet perforating tool into the well on a production tubing string; (4) perform a perforating or cutting job with the jet perforating tool; (5) run the jet perforating tool out of the well on the production tubing string; (6) run the production tubing string back into the well; and (7) run the pump rods and pump back into the well.
Each of steps 2, 3, 5, and 6 involve the process of running production tubing into or out of the well. These processes typically may take several or more hours to perform. The deeper the well, the longer these processes take. Thus, these conventional methods for performing these well operations are time consuming and expensive, especially for deeper wells.
Certain modifications to the aforementioned process have reduced the time to run a jet perforating tool into the well. For example, temporary tubing work strings may be used, such as coiled tubing. Coiled tubing cuts the trip time associated with running conventional production tubing into and out of the well. But, coiled tubing is costly in its own right and requires a secondary system to be on location at the well site.